Wire Advancing Device

ABSTRACT

The invention relates to a wire advancing device for conveying a wire, particularly a welding rod, from a wire supply to a useful point with the aid of conveying means. The wire advancing device comprises a mechanism for adjusting the contact pressure applied to the welding rod by the conveying means. In order to create a wire advancing device which is provided with little slip and can be used for welding rods that have a different diameter and are made of different material, the adjusting mechanism encompasses at least one elastically or plastically deformable pressing means which acts upon the conveying means and is connected to a supply unit. The pressing means is filled with a gaseous or liquid medium via the supply unit in order to adjust the contact pressure applied to the welding rod by the conveying means.

The invention relates to a wire transport device for transporting a wire, in particular a welding wire, by the aid of transport means from a wire supply to a point of consumption, including an adjustment device for adapting the contact pressure exerted by the transport means on the welding wire.

The systems known from the prior art have used different wire transport devices or drives, which, as a rule, have large dimensions and are subject to high slip and wear. The majority of those wire transport devices is merely applicable to predetermined, set welding wires such that but a single welding wire having a preadjusted welding wire diameter or material can be transported by the respective wire transport device. At an exchange of the welding wire, components of the wire transport device will have to be exchanged, or newly adjusted, as a function of the material and diameter of the selected welding wire in order to ensure the optimum wire transport.

Also known are wire transport devices in which different welding wires can be transported by the aid of resilient elements pressing on transport means. There, the contact pressure will, however, be substantially higher with a larger welding wire diameter than with a thinner welding wire. Moreover, no influence can be taken on the composition of the welding wire in those wire transport devices, which means that, for instance, in the event of a welding wire having a high aluminum content, the surface of the welding wire will be substantially more easily deformable than that of a welding wire containing a high portion of elements harder than aluminum.

Those wire transport devices are, thus, able to convey welding wires having different diameters and even different compositions, yet do not allow any influence to be exerted on the contact pressure, for which reason deformations of the welding wire may, for instance, occur at too high a contact pressure, and it may happen, for instance at too low a contact pressure, that the transport means will slip through, i.e. have a high slip, thus rendering a constant welding wire transport impossible.

The object of the present invention consists in providing an above-defined wire transport device of low slip, by which the welding wire will be deformed as slightly as possible. Another object of the invention consists in enabling the transport of welding wires having different diameters. The adaptation of the contact pressure of the transport means to the employed welding wire is to occur automatically and be independently controlled by the welding apparatus.

The objects of the invention are achieved in that the adjustment device comprises at least one elastically or plastically deformable pressure means which acts on the transport means and is connected with a supply unit. The advantage resides in that it is feasible to use a simple pressure means known from the prior art and constructed in a simple manner, and the wire transport device is, thus, automatically adjusted to the welding wire inserted or used. Another advantage resides in that, at a change of the welding wire, i.e. if a different welding wire is required for a welding process, no components of the wire transport device need be exchanged in order to safeguard a problem-free wire transport, so as to provide a substantially simplified handling of the wire transport device.

In order to ensure an appropriate action of the pressure means on the transport means, the pressure means is advantageously arranged between a transport means and a supporting surface or supporting element provided on the opposite side of the transport means.

The connection between the pressure means and the supply unit can be realized by lines and/or bores and/or flow channels.

The plastically or elastically deformable pressure means can be formed by a pressure hose or a pneumatic pad. Thereby, a simple pressure control and, hence, simple adaptation to the respectively used welding wire is feasible by the pressure means. No components of the wire transport device need be exchanged at a change of the welding wire and, in particular, with a larger or smaller welding wire diameter. This renders feasible a highly cost-effective construction of the pressure transport device while, at the same time, allowing the precise pressure adaptation of the contact pressure in a simple manner.

The pressure hose is advantageously closed on one end and comprises a filler neck for supplying a medium The pressure control of the pressure means is thereby readily feasible by supplying or discharging said medium.

The filler neck may be connected via a line with a container containing said medium and constituting the supply unit The container constituting the supply unit can be arranged either within the welding apparatus or outside the welding apparatus.

The container can be comprised of a gas bottle or a pressure vessel. Thus, any container known from the prior art may be used for the medium, with an independent pressure system being thereby provided for the adaptation of the pressure of the pressure means.

If the medium contained in the pressure means is comprised of a gas, no additional container or pressure vessel will be required, since the gas or shielding gas employed for the welding process can be used to build up the pressure within the pressure means.

Said medium can also be comprised of a fluid, thus providing a simple medium to be renewed or refilled at any time.

The transport means can be comprised of rollers, or elements arranged to circulate, for instance, in a transport element.

This ensures the safe transport of the welding wire.

According to a further characteristic feature of the invention, it is provided that the contact force exerted by the transport means on the respective welding wire is adjustable via the welding apparatus and/or a control device and/or an operating panel and/or a remote control.

In doing so, the thickness and material of the employed welding wire are, above all, entered.

In order to ensure the automatic adjustment of the contact pressure, a device for controlling the contact pressure of the transport means is advantageously provided, which will control the contact pressure as a function of the values respectively set for the employed welding wire, in particular its thickness and/or material. A user of the welding apparatus will merely have to identify the employed welding wire, i.e., for instance, the material and thickness or diameter used for the welding wire, whereupon the automatic control of the contact pressure will be performed by the welding apparatus or control device.

According to a further characteristic feature of the invention, a device for detecting the actual value of the pressure exerted by the transport means on the welding wire, or also a device for detecting the actual value of the speed of the welding wire, is provided. This will enable the determination of the wire transport speed and, hence, for instance, also the slip of the transport means as well as the adaptation of the pressure of the adjustment device by the welding apparatus and/or control device and/or operating panel. The contact pressure will, thus, for instance, be increased with slipping transport means in order to reduce such slips.

A manual adjustment of the pressure to the required conditions is feasible by the user by the aid of a manual pump and, optionally, a valve.

The present invention will be explained in more detail by way of the annexed drawings.

Therein:

FIG. 1 is a schematic and simplified illustration of a welding machine or welding apparatus;

FIG. 2 is a schematic and simplified illustration of a welding torch with a partial section through the welding torch in the region of the wire transport device;

FIG. 3 is a schematic and simplified illustration of a welding torch with a partial section through the welding torch in the region of the wire transport device;

FIG. 4 is a schematic, simplified sectional view of a detail of the wire transport device according to the invention;

FIG. 5 is a view on the wire transport device according to FIG. 4 in the direction of the welding wire.

FIG. 1 depicts a welding apparatus 1, or welding installation, for various processes or methods such as, e.g., MIG/MAG welding or WIG/TIG welding, or electrode welding methods, double-wire/tandem welding methods, plasma or soldering methods etc.

The welding apparatus 1 comprises a power source 2 including a power element 3, a control device 4, and a switch member 5 associated with the power element 3 and the control device 4, respectively. The switch member 5 and the control device 4 are connected with a control valve 6 arranged in a feed line 7 for a gas 8 and, in particular, a shielding gas such as, for instance, carbon dioxide, helium or argon and the like, between a gas reservoir 9 and a welding torch 10 or torch.

In addition, a wire feeder 11, which is usually employed in MIG/MAG welding, can also be activated by the control device 4, an additional material or welding wire 13 being fed from a wire supply 14 or feed drum into the region of the welding torch 10 via a feed line 12. It is, of course, possible to integrate the wire feeder 11 in the welding apparatus 1 and, in particular, its basic housing as is known from the prior art, rather than designing the same as an accessory device as illustrated in FIG. 1.

It is also possible for the wire feeder 11 to supply the welding wire 13, or filler material, to the process site outside the welding torch 10, to which end a non-consumable electrode is preferably arranged within the welding torch 10, as is usually the case with WIG/TIG welding.

The power required to build up an electric arc 15 between the electrode and a workpiece 16 is supplied from the power element 3 of the power source 2 to the welding torch 10, in particular electrode, via a welding line 17, wherein the workpiece 16 to be welded, which is formed of several parts, is likewise connected with the welding apparatus 1 and, in particular, the power source 2 via a further welding line 18, thus enabling an electric circuit for a process to build up over the electric arc 15, or over the plasma jet formed.

To provide cooling of the welding torch 10, the welding torch 10 can be connected to a fluid reservoir 21, particularly a water reservoir, by a cooling circuit 19 via an interposed flow control 20, whereby the cooling circuit 19 and, in particular, a fluid pump used for a fluid contained in the water reservoir 21, is started as the welding torch 10 is put into operation, so as to effect cooling of the welding torch 10.

The welding apparatus 1 further comprises an input and/or output device 22, via which the most different welding parameters, operating modes or welding programs of the welding apparatus 1 can be set and called, respectively. In doing so, the welding parameters, operating modes or welding programs set by the input and/or output device 22 are transmitted to the control device 4, which, in turn, will subsequently activate the respective components of the welding apparatus 1 and determine the respectively desired values for controlling.

Furthermore, the welding torch 10 in the exemplary embodiment illustrated is connected with the welding apparatus 1 or welding installation via a hose pack 23. The hose pack 23 accommodates the individual lines from the welding apparatus 1 to the welding torch 10. The hose pack 23 is connected with the welding torch 10 via a coupling device 24, whereas the individual lines arranged in the hose pack 23 are connected with the respective connections of the welding apparatus 1 via connection sockets or plug-in connections. In order to ensure the appropriate strain relief of the hose pack 23, the hose pack 23 is connected with a housing 26, in particular the basic housing of the welding apparatus 1, via a strain relief means 25. It is, of course, also possible to use the coupling device 24 for the connection to the welding apparatus 1.

It should basically be noted that not all of the previously mentioned components need be used or employed for the various welding methods or welding apparatus 1 such as, e.g., WIG devices or MIG/MAG apparatus or plasma devices. Thus, it is, for instance, possible to realize the welding torch 10 as an air-cooled welding torch 10.

FIGS. 2 to 5 are simplified, schematic illustrations of exemplary embodiments of the automatic contact pressure adjustment according to the invention realized during wire transport.

FIG. 2 illustrates a welding torch 10 in a simplified schematic side view. In this exemplary embodiment, a wire transport device 27 is arranged in the welding torch 10. The region of the welding torch 10, in which the wire transport device 27 is arranged, is shown in a partially sectioned illustration.

Furthermore, a transport means 28 is arranged in the wire transport device 27, which is comprised of at least one drive roller 29 and at least one pressure roller 30. The drive roller 29 is connected with a shaft 31 in a rotationally fast manner.

The shaft 31 can be connected, for instance via a gear, with a drive 32, in particular a drive motor, or directly with the drive 32. In order to exert a pressure on the welding wire 13 to cause the transport of the latter, the pressure roller 30 is arranged on the side located opposite the welding wire 13, of the drive roller 29. The pressure roller 30 is arranged to be movable in the direction of the welding wire 13 and journalled on a further shaft 33, which shaft 33 is arranged to be adjustable, for instance, along a groove 34. On the side located opposite the groove 34, of the pressure roller 30, an adjustment device 35 comprising a pressure means 36 is arranged. The pressure means 36 can be realized in a plastically or elastically deformable manner and is arranged between the transport means 28, in particular pressure roll 30, and, on the side located opposite the transport means 28, a supporting surface or supporting element 37. The pressure roller 30, by the aid of the pressure means 36, presses against the welding wire 13 inserted in the wire transport device 27, thus pressing the same against the drive roller 29. This causes the welding wire 13 to be clamped within the transport means 28 and conveyed by the drive roller 29 in the respective direction, i.e., for instance, in the direction of the workpiece 16 or in the opposite direction. In order to enable the transport of a welding wire 13 having different properties, the pressure means 36 will have to be exchanged so as to again provide the contact pressure on the welding wire 13 required for a smooth wire transport and, hence, ensure the safe and problem-free transport of the welding wire 13.

In the embodiment according to FIG. 3, the pressure means 36 is, for instance, formed by a pressure hose 38. The pressure means 36, or pressure hose 38, is again arranged between the transport means 28, in particular pressure roller 30, and the supporting element 37 and connected with a supply unit 39, in particular a container, via a line 40 and/or bores and/or flow channels. The supply unit 39 or container can, for instance, be arranged within the welding apparatus 1, or also outside the welding apparatus 1, yet such an arrangement is not illustrated in this exemplary embodiment. The pressure hose 38 is closed on one end and comprises a filler neck 41 on its end facing the line 40. The line 40 is slipped on, and fastened to, said filler neck 41. The pressure means 36, i.e. the pressure hose 38, and the filler neck 41 are, thus, connected via line 40 with the supply unit 39, which may be arranged within the welding apparatus i or also outside the same, i.e. externally. A medium 42, which is introduced into the pressure hose 38 through line 40, is provided in the supply unit 39. In order to build up a pressure within the pressure hose 38 to inflate the latter in a manner that the pressure hose 38 is being pressed against the transport means 28, in particular pressure roller 30, thus causing the same to press the welding wire 13 against the drive roller 29, a valve, in particular a proportional pressure control valve 43, is, for instance, provided in addition. The proportional pressure control valve 43 is not described in detail, because it is well known in the art. The pressure control valve 43 can be arranged in the supply unit 39 and/or in the line 40. The user, thus, enters the employed welding wire 13 into the welding apparatus 1 or control device 4 so as to cause the welding apparatus 1 or control device 4 to automatically control the contact pressure exerted by the transport means 28, in particular pressure roller 30, on the welding wire 13. This is effected in a manner that the control device 4 transmits the necessary values, in particular pressure values, for the employed welding wire 13 to the pressure control valve 43. It is, of course, also possible to notify the welding apparatus 1 and/or the operating personnel and/or the control device 4 of the thickness and material of the welding wire 13, whereupon, for instance, the control device 4 will control the contact pressure accordingly.

The welding apparatus 1, or control device 4, and the pressure control valve 43 activated by the control device 4 will, thus, automatically control the pressure, in particular contact pressure, exerted by the transport means 28, in particular pressure roller 30, on the welding wire 13. This ensures the safe transport of the welding wire 13 without causing the pressure roller 30 and the drive roller 29 to slip or the welding wire 13 to deform.

It is, of course, also possible to replace the proportional pressure control valve 43 with any means known from the prior art to build up a pressure in the pressure means 36. The pressure build-up in the pressure means 36 can, for instance, also be realized by using a manual pump instead of the pressure control valve 43. The user will, thus, be able to individually control the pressure by the manual pump. Furthermore, a device for detecting the actual value of the pressure prevailing in line 40, i.e. between the pressure control valve 43 and the filler neck 41, may also be provided, with the actual pressure value being, for instance, indicated by a manometer.

The employed medium 42 can, for instance, be comprised of a fluid, yet it is also possible to use a gaseous medium 42 in the pressure means 36. In an advantageous manner, the shielding gas of the welding process can be used as said medium 42. Since only small amounts of medium 42 are required for a smooth pressure adjustment, the welding process will in no way be thereby influenced. In this case, the supply unit 39 may, of course, be formed by a gas bottle or a pressure vessel.

The pressure means 38 can also be comprised of a pneumatic pad known from the prior art, which pneumatic pad will likewise comprise a filler neck 41 to be filled with a medium 42. The pneumatic pad may again be filled with a fluid or gaseous medium 42 such as, e.g., air or a gas, and activated and controlled by the welding apparatus 1 and control device 4, respectively. The medium 42 may, thus, again be comprised of the shielding gas respectively used for the welding process. No additional container will, thus, be required for the medium 42.

FIGS. 4 and 5 are simplified schematic illustrations of a further variant embodiment of the wire transport device 27 including an automatic pressure adaptation to the welding wire 13.

The wire transport device 27 in this case is comprised of a base body 44 with a retaining element 46 being inserted in a central recess 45 of the base body 44. The retaining element 46 is, for instance, mounted in the-interior of the base body 44 via at least one bearing 47. The at least one bearing 47 is secured against falling out by rings 48 arranged in the recess 45 of the base body 44. Said rings 48 may be formed by known circlips. The retaining element 46 projects beyond the base body 44 on either side. A socket 49, which is connected with the retaining element 46 in a rotationally fast manner, is arranged on one side. Normally to the welding wire 13 in the socket 49 may extend a thread 50, into which a headless pin 68 is screwed until contacting the retaining element 46 to connect the socket 49 with the retaining element 46 in a rotationally fast manner. On the opposite side of the socket 49 is arranged a reception element 51 onto which a retaining ring 52 is slipped. The reception element 51 further comprises a projection 53 onto which the pressure means 35, in particular pressure hose 38, is slipped. The pressure hose 38 will then extend from the reception element 50 as far as to at least one transport element 54 or at least one pressure element 55. The transport element 54 and the pressure element 55 are arranged within the retaining element 46 around the welding wire 13.

A bore 56 is arranged within the reception element 51, particularly centrically to the projection 53, running into a further radially arranged bore 57. At least one circumferential groove 58 into which the bore 57 opens is arranged within the retaining ring 52. Two further grooves 59 may be arranged on the two sides of the groove 58, being, for instance, configured as seals relative to the groove 58, into which known O-rings may, for instance, be inserted. Moreover, a supply bore 60 is arranged normally to the central axis of the retaining element 46, running into the groove 58.

Via the supply bore 60, the medium 42 is introduced into the groove 58 and reaches the bore 56 via the bore 57 provided in the reception element 51, and the pressure hose 38 via the projection 53. A simple and uncomplicated supply of medium 42 to the pressure element 36, in particular pressure hose 38, is, thus, ensured.

In the exemplary embodiment illustrated, a pressure element 55 and two transport elements 54 are, for instance, arranged about the welding wire 13 at 120°. The transport elements 54 are rigidly arranged within the retaining element 46, while the pressure element 55 is mounted in the retaining element 46 so as to be movable in the direction towards the welding wire 13. A pressure is exerted by the pressure hose 38 on the pressure element 55, which in turn exerts a pressure on-the welding wire 13, thus forming an active connection between the welding wire 13, the transport element(s) and the pressure element 55. The welding wire 13 is, thus, driven and, hence, conveyed by the transport elements 54 and the pressure element 55.

In the transport element 54, elements 61 are arranged to circulate along a guide track and, on the side facing the welding wire 13, partially extend outside the transport element 54. The elements 61 extend outside the transport element 54 by such an extent that they will not fall out of the transport element 54, yet contact the welding wire 13. On the transport element side located opposite the welding wire 13, the elements 61 run again partially outside the transport element 54, engaging an internal thread 62 provided in the interior of the base body 44 of the wire transport device 27, i.e. in the recess 45. By rotating the base body 44 of the wire transport device 27, the elements 61 engaging the inner thread 62 will be displaced along the guide track of the transport element 54. The welding wire 13 is, thus, displaced and, in particular, transported by the elements 61 acting on the welding wire 13 and the thus forming active connection.

The pressure element 55 in this exemplary embodiment is comprised of at least two parts, between which at least one roller 63 is arranged. The at least one roller 63 is rotationally mounted on an-axis 64 and partially projects out of the pressure element 55 so as to be able to exert a pressure on the welding wire 13. The pressure means 36 or pressure hose 38, respectively, is arranged on the side of the roller 63 opposite the welding wire 13. The pressure hose 38 can be slipped onto the projection 53 of the reception element 51, yet may also be fastened to the projection 53 or reception element 51 in any other way. The pressure element 55 is displaced in the direction of the welding wire 13 by the pressure hose 38. To this end, the pressure hose 38 is filled with medium 42 as described above.

In the welding apparatus 1, merely the employed welding wire 13 has to be entered by specifying, for instance, its diameter and material. The pressure exerted on the transport element 54 by the pressure hose 38 and, hence, acting on the welding wire 13, will then be automatically controlled by the welding apparatus 1, i.e., the control device 4 of the welding apparatus 1. Consequently, no further adjustments or adaptations need be performed by the user to provide the optimum wire transport.

Moreover, a change of the welding wire 13 does not require a change of the components necessary for the wire transport and, in particular, the transport means 28 so as to enable the simple, uncomplicated handling of the wire transport device 27.

In order to displace the elements 61 by the internal thread 62 extending within the transport element 54, the base body 44 is rotated about its central axis. This causes the elements 61 to be displaced along the guide track of the transport element 54. The base body 44 of the wire transport device 27 can, for instance, be driven via a V-belt or toothed belt 65, which is tensioned via the base body 44 and a drive 66, or a shaft 67 of the drive 66. In a preferred manner, the drive 66 is arranged in parallel with the wire transport device 27, i.e. laterally of the wire transport device 27. It is, of course, also possible to arrange the drive 66 centrically to the welding wire 13, or wire transport device 27, with the welding wire 13 being conducted through the drive 66, which is designed as a hollow shaft drive. Thus, a structurally very small wire transport device 27 can be provided in a simple manner, which may, for instance, be arranged in the welding torch 10.

The wire transport device 27 according to the invention can also be arranged in the welding apparatus 1 and/or in or down-stream of the wire supply 14 and/or in the hose pack 23. 

1. A wire transport device (27) for transporting a wire, in particular a welding wire (13), by the aid of transport means (28) from a wire supply (14) to a point of consumption, including an adjustment device (35) for adapting the contact pressure exerted by the transport means (28) on the welding wire (13), wherein the adjustment device (35) comprises at least one elastically or plastically deformable pressure means (36) which acts on the transport means (28) and is connected with a supply unit (39).
 2. A wire transport device (27) according to claim 1, wherein the pressure means (36) is arranged between a transport means (28) and a supporting surface or supporting element (37) provided on the opposite side of the transport means (28).
 3. A wire transport device (27) according to claim 1, wherein the pressure means (36) is connected with the supply unit (39) via a line (40) and/or a bore (56, 57) and/or flow channels.
 4. A wire transport device (27) according to claim 1, wherein the pressure means (36) is, for instance, formed by a pressure hose (38).
 5. A wire transport device (27) according to claim 1, wherein the pressure means (36) is formed by a pneumatic pad.
 6. A wire transport device (27) according to claim 4, wherein the pressure hose (38) is closed on one end and comprises a filler neck (41) for supplying a medium (42).
 7. A wire transport device (27) according to claim 6, wherein the filler neck (41) is connected via a line (40) with a container containing said medium (42) and constituting the supply unit (39).
 8. A wire transport device (27) according to claim 7, wherein said container is comprised of a gas bottle or a pressure vessel.
 9. A wire transport device (27) according to claim 6, wherein the medium (42) contained in the pressure means (38) is comprised of a gas.
 10. A wire transport device (27) according to claim 6, wherein the medium (42) contained in the pressure means (38) is comprised of a fluid.
 11. A wire transport device (27) according to claim 1, wherein the transport means (28) is comprised of rollers, or elements (61) arranged to circulate, for instance, in a transport element (54).
 12. A wire transport device (27) according to claim 1, wherein contact force exerted by the transport means (28) on the respective welding wire (13) is adjustable via the welding apparatus (1) and/or a control device (4) and/or an operating panel and/or a remote control.
 13. A wire transport device (27) according claim 1, wherein a device for controlling the contact pressure of the transport means (28) is provided.
 14. A wire transport device (27) according to claim 1, wherein a device for detecting the actual value of the pressure exerted by the transport means (28) on the welding wire (13) is provided.
 15. A wire transport device (27) according to claim 1, wherein a device for detecting the actual value of the speed of the welding wire (13) is provided.
 16. A wire transport device (27) according to claim 1, wherein a manual pump is provided for the manual adjustment of the contact pressure of the transport means (28).
 17. A wire transport device (27) according to claim 16, wherein a valve, in particular a proportional pressure control valve (43), and a manometer are provided. 